;(function($){
	$.fn.navfix = function(mtop,zindex){
		var nav = $(this),
		mtop = mtop,
		zindex = zindex,
		dftop = nav.offset().top-$(window).scrollTop(),
		dfleft = nav.offset().left-$(window).scrollLeft(),
		dfcss = new Array;
		dfcss[0] = nav.css("position"),
		dfcss[1] = nav.css("top"),
		dfcss[2] = nav.css("left"),
		dfcss[3] = nav.css("zindex"),
		$(window).scroll(function(e){
			$(this).scrollTop()>dftop?
			nav.css({
				position:"fixed",
				top:mtop+"px",
				left:dfleft,
				"z-index":zindex
			}):
			nav.css({
				position:dfcss[0],
				top:dfcss[1],
				left:dfcss[2],
				"z-index":dfcss[3]
			})
		})
    }
})(jQuery)